1. Field of the Invention
The present invention relates to an ultrasonic switching device delivering an electric signal by touching a surface of a piezoelectric substrate.
2. Description of the Prior Art
Conventional methods for exciting an acoustic vibration on a nonpiezoelectric plate generally include a wedge-shaped transducer with a bulk wave vibrator for vibrating a nonpiezoelectric plate indirectly, or a piezoelectric thin film transducer for vibrating a nonpiezoelectric plate directly. These conventional-type transducers are applied to, for example, touch panels making use of decreasing or disappearance of output electric signal in accordance with decreasing or disappearance of an acoustic wave on a nonpiezoelectric plate when touching thereon. Such touch panels cause a high voltage operation with a high power consumption, a large-scale circuit with a complicated structure, and a difficulty on remote control. Moreover, there are some problems on manufacturing and operation frequencies.
Thus, it was difficult to apply the conventional-type transducers to a switching device delivering an electric signal by touching a surface of a piezoelectric substrate.